Suction box belt



SUCTION BOX BELT 3 Sheets-Sheet 1 Filed Jan. 26, 1960 064/ J. .jusrus Feb. 19, 1963 w. E. PERKINS ETAL SUCTION BOX BELT 3 Sheets-Sheet 2 Filed Jan. 26, 1960 INVENTORS. M04059 5. PEEK/IVS [0 6A 2 Ill- J08 706' Feb. 19, 1963 w. E. PERKINS ETAL 3,077,925

SUCTION BOX BELT Filed Jan. 26, 1960 3 Sheets-Sheet 3 IN VEN TORS- w/zpae E. PER/W05 50642 J. Jusras 3,077,925 SUCTION 30X BELT Wilder E. Perkins, Nutley, N..l., and Edgar J. Justus,

Beloit, Wis, assignors of one half to Rayhestcs-Vlanhattan, Inc., Passaic, Ni, a corporation of New Jersey, and one-half to Beloit Iron Works, Beloit, WES., a corporation of Wisconsin Filed Jan. 26, 1960, Ser. No. 4,648 9 Claims. (Cl. 162-367) This invention relates to improvements in belts for suction boxes used in Fourdrinier paper making machines.

Of the several types of machines used in making paper, the Fourdrinier machine produces paper at the fastest rate and in the greatest tonnages per day. Modern machines of this type are run at a speed of 2000 to 2200 feet per minute and some are being erected to be run from 2500 to 3000 feet per minute, the high speed being desired for producing paper quickly and at a lower cost. This increased, and ever increasing, speed, however, has produced and produces problems relating to the wear of the machine parts.

As is known, in the Fourdrinier machine, a slurry of wood pulp fibres in water is fed evenly to a movable wire screen, the wire screen being used to permit the water to drain or be sucked out of the pulp. The pulp which is fed on to the wire screen contains less than 1% fibre and more than 99% water; and until most of the water is removed from the paper, the paper is too weak to carry itself through the remaining water removal steps. It is therefore, essential to remove the water as quickly as possible; and this is even more important with machines of increased speed.

In high speed Fourdrinier machines, the Water is removed by means of suction boxes, the number of which may vary from a few to as many as a dozen or more. A suction box comprises a metal box with a perforated cover placed up against the bottom of the wire screen over and in contact with which cover the wire screen is moved. A vacuum is maintained on the suction box, and the water is drawn into the boxes through the drainage perforations in the cover. The greater the suction applied, the more water is removed, thereby permitting higher speeds or less further drying capacity.

The higher speed machines and the higher suction applied have introduced serious problems concerning the wear of the machine parts, due to the increased friction between the moving wire screen and the suction box cover. While slow machines operating at from 500 to 600 feet per minute will often have wires that wear for a period of months before they wear out or break, in higher speed machines the useful life of the wire will be from four to ten days, and the 1200 to 1500 feet per minute machines used in making heavy kraft paper can wear out a wire screen in from three to five days. It is estimated that roughly 80% of the wire wear occurs due to the friction developed over the suction boxes. Wire screens are quite costly, but the biggest expense is incurred in the stoppage of the machines which is necessitated by changing the wire screens. It has been estimated that a wire change will cost, in wire, labor and loss of production, between ten to fifteen thousand dollars.

Wire life is increased by the employment of a revolvable belt, such as is shown in the patent to Evans No. 2,039,308 of May 5, 1936, which belt carries the Fourdrinier wire over the suction box and which belt is provided with drainage perforations or holes which in the movement of the belt over the suction box cover are designed to move in alinement with the drainage perfora- 3,077,925 Patented Feb. 19, l 963 tions or holes formed in the suction box cover. The wire is supported by the belt and the belt takes the wear, instead of the wire, since the belt and wire travel together (and at the same speed) over the suction box cover. The belt is run loosely over supporting rolls or pulleys and is driven by the wire through surface suction contact. The belt itself, the body of which is made of rubber, running wet over smooth Micarta, bronze or maple wood commonly used for suction box covers is itself very durable. Wire wear is thereby substantially decreased and the cost of a wire replacement or change is materially reduced.

Such wire carrying belts are formed with numerous laterally extending and laterally spaced drainage channels also closely spaced longitudinally of the belt and its travel; and each channel is provided with a number of drainage holes, with the result that a sizable belt has to be formed with a large number of such channels and a still larger number of drainage holes. With belts of increased size, such as belts having a width of 20 feet or over and a circumference of 25 feet, the number of drainage holes which must be formed in the belt runs into the several thousands. As indicated above, these drainage holes, which are arranged in a set pattern, must move in alinement with the drainage holes in the suction box cover to enable the proper suction functioning of this part of the Fourdrinier machine. The problem of securing and maintaining such alinement is a critical one, and becomes all the more so as larger belts of the type referred to are constructed and used.

The prime object of the present invention pertains to the provision of a suction box belt constructed and de signed to effectively solve this problem of securing and maintaining the alinement between the belt drainage holes and the suction box drainage holes in the continuing operation of the F ourdrinier machine.

We have found that this may be accomplished by a belt comprising a flexible rubber casing body, the en cased strength member of which comprises a fabric built to inhibit in use lateral dimensional changes, i.e., either growth or shrinkage in the belt width, despite the removal of a substantial proportion of the belt body occasioned by the many channels and the numerous drainage holes that are cut from and punched into the belt, the desired alinement between the belt drainage holes and the suction box drainage holes being thereby initially secured and maintained over long usage.

To the accomplishment of the foregoing object and such other objects as may hereinafter appear, our invention relates to the suction box belt as more particularly defined in the appended claims taken together with the following specification and the attached drawings in which:

FIG. 1 is a vertical elevational view of a section of a Fourdrinier machine showing the application thereto of a belt embodying the principles of the present inventron;

FIG. 2 is a top plan view thereof with parts broken away and other parts in section shown for explanatory purposes;

FIG. 3 is a top plan View of a section of the belt depicting an exemplary pattern of drainage channels and drainage holes provided therein;

FIG. 4 is a fragmentary view on an enlarged scale of the view shown in FIG. 3;

FIG. 5 is a view of the belt section of FIG. 4, shown on a still larger scale, and taken in cross-section in the plane of the line 5-5 of FIG. 4;

FIG. 6 is a vertical elevational View of the belt section of FIG. 4 taken in cross-section in the plane of the line 66 of FIG. 4;

FIG. 7 is an enlarged fragmentary perspective view of a section of the belt with parts stepped for explanatory purposes;

FIG. 8 is a perspective view of a section of a woven fabricated sheet which forms an essential component of the strength member of the belt;

FIG. 9 is a view of FIG. 8, shown to a larger scale, and taken in cross-section in the plane of the line 9--9- of FIG. 8;

FIG. 10 is a view of FIG. 8, also shown on an enlarged scale, taken in cross-section in the plane of the line 10-10 of FIG. 8;

FIG. 11 is a perspective view of the Woven fabricated sheet section of FIG. 8 after the same has been rubber impregnated to produce one of the plies of the strength member of the belt; and

FIG. 12 is a fragmentary view on an enlarged scale taken in cross-section in the plane of the line 12-42 of FIG. 11.

Referring now more in detail to the drawings and having reference first to FIGS. I and 2 thereof, there is shown an improved construction of a section of a Fourdrinier machine of the type shown in the patent to Evans No. 2,939,308 of May 5, 1936 with which the belt of the present invention is employed. This machine comprises in its essential parts a suction box S mounted on a supporting framework F, the said suction box being provided with a suction box cover C over which is moved a revolvaole belt B which carries the Fourdrinier wire W. The belt B runs loosely over end pulleys P and P, the bottom bight of the belt being supported on and running over supporting rolls R and R The suction box cover C, which is customarily made of Micarta, maple wood, bronze, or similar materials, is formed or provided with laterally spaced groups of longitudinally disposed drainage holes or perforations 20.

The belt B comprises an endless flexible rubber casing body specially constructed as hereinafter described, said belt being provided with laterally extended and laterally spaced drainage channels 22, 22, each in turn provided with one or more drainage holes 24, 24, said drainage holes 24 being patterned to provide laterally spaced groups of longitudinally disposed drainage holes, the patterning being such that in the movement of the belt over the suction box cover the longitudinally disopsed drainage holes 24 are alined with the longitudinally disposed drainage holes 20, 20 in the suction box cover, as will be seen particularly by reference to FIG. 2 of the drawings. The belt B at its opposite sides or ends is also preferably provided with short channels 22 in which are also formed drainage holes for alinement with drainage holes 20 formed in the sides or ends of the suction box cover. The Fourdrinier wire is trained for movement over end couch rolls, one such couch roll 26 being shown in FIG. I of the drawings' In the operation of the machine the belt B is run loosely over the end pulleys P and P and the bottom supporting rolls R and R the belt being driven by the wire through surface suction contact therewith, the belt and the wire moving together in the direction indicated by the arrows in FIG. 1 of the drawings.

FIGS. 3 and 4 of the drawings depict an exemplary patterning and structure of the drainage channels that are formed in the belt and the drainage holes that are punched therein. As shown in FIG. 3, which depicts a section of the belt, the drainage channels 22 extend laterally or transversely of the belt and are closely spaced longitudinally of the belt in interrupted and staggered relation. With a belt having a width dimension of 20 feet or more, the channels 22 may each be from 1 to 2 feet long and the longitudinal center to center spacing of these channels may be about 78'. The channels in the two rows of channels 22 on the sides or ends of the belt may each be about 1 /2 inches long. The channels are milled into the rubber after curing of the belt, or they may be formed in the molding of the belt. Each channel 22 is in turn provided with a plurality of the drainage holes 24, 24, which in the pattern shown in FIG. 3 are shown staggered, but which, are already indicated, define groups of laterally spaced and longitudinally disposed and alined drainage holes. These holes 24 are punched in the belt and as shown in FIG. 4 of the drawings, they are preferably oval in shape, having a dimension such as x The side drainage channels are in turn provided with drainage holes 28, 28, which may be circular in form. It will be understood that the patterning of the channels and holes maybe considerably modified and varied, an exemplaryarrangement being depicted in the drawings. It will therefore be seen that, with a belt having dimensions such'as 20 feet wide and 25 feet in circumference, that the number of channels or grooves 22 run into the thousands and that thenumber of drainage holes 24 are multiplied in the thousands.

For the successful operation and use of a belt of this character, and particularly of these dimensions, it is requisite, in order to initially secure and maintain alinement between the belt drainage holes and the suction box drainage holes, that lateral dimensional changes, i.e'.', either the growth or shrinkage in the belt width be in} hibited or greatly minimized despite the removal of so much of the belt body occasioned by the many channels and the numerous drainage holes that are cut from and punched into the belt. To accomplish this the belt of the present invention is made to comprise a flexible rubber casing body formed with an encased strength member which latter is especially designed and built to inhibit or minimize such lateral dimensional changes. In a belt having a width of 20 feet or more such changes in the overall width of the belt in the operation of the apparatus should not exceed /2. The criticalness of this requirement will be the better appreciated when it is noted that rubber is not waterproof and is subject to shrinkageor growth, particularly when the belt becomes'saturated with moisture from the hot paper pulp (up to 160 F.) or cold paper pulp rushing through the channels and'holes in copious volume.

To solve this critical problem, the belt B of the present invention comprises a rubber casing 30 providedwitlia strength member designated'as 32, which strength member comprises a plurality of laminated plies of rubber impregnated fabric sheets 34, five of such fabric sheets being shown in the drawings, each sheet comprising'a fabric woven transversely essentially and preferably solely with straight metal wire 36, 36 and longitudinally with an interlaced yarn warp 38, 38, the metal fillerwire functioning to inhibit or minimize the changes in the width dimensions of the belt in use, and the yarn warp functioning to maintain belt flexibility in a belt longitudinal direction. This structure of the belt in its assembly is best depicted in FIGS. 5 to 7 of the drawings. For a fuller understanding of the construction of each sheet of the laminated plies, reference may now be had to FIGS. 8 to 12 of the drawings.

FIGS. 8 to 10 illustrate the structure of .the fabric prior to rubber impregnation. The warp yarn orfibre 38 is preferably cotton, but may be rayon, nylon, Dacron, or similar synthetic fibre, or even glass. The filler (woofs) wire 36 may be any type of rust resistant metal wire, such as brass, stanless steel, bronze and aluminum. For the purpose of obtaining good rubber bonding the warp fibre should be substantial in size compared to the filler wire. Also for purposes of good bonding we prefer to use brass wire with 60% to copper. We have'found successful fabric sheets to be obtained with cotton yarn 12/3 warp and 7030 brass wire, .007" gauge'woof, with the fabric woven with woof as tight as possible (no crimp). It is important that the filler wire 36 be straight, the same being interlaced with the yarnwarp as indicated in FIGS. 8 to 10 of the drawings.

The fabric sheet thus constructed is then rubber impregnated, producing a rubber coating or casing 40 for the sheet which is bonded to both thewire fillers and the acraaas fiber warps of the fabric as best shown in FIGS. 11 and 12 of the drawings.

A plurality of plies of such impregnated fabric sheets are then built up as shown in FIG. 7 of the drawings onto an abrasion resistant rubber base over which is applied a top cover of abrasion resistant rubber. The belt is built up in conventional manner but with great care in laying the fabric so as to be certain that the filler (woof) Wires are square with the longitudinal belt direction. Seams and splices are carefully butted to assure no overlaps or gaps.

It may be pointed out that strength and stretch in the longitudinal direction of the belt are of little importance in the belt of the present construction. The belt operates flat, not troughed, and simply functions to carry the wire. The belt is not required to snugly wrap the pulleys or the rolls and changes in length or stretch of the belt are not material. Moreover, it is desired to have the belt as flexible as possible in a longitudinal direction; and therefore the warp strands are desirably limp and flexible and are made only of a fibre material.

To produce the desired width control the filler or woof should be made essentially and preferably solely of the straight metal wire, since any material amount of fibre in the woof direction would increase the possibility of width changes from heat or moisture absorption.

The manner of constructing or building the suction box belt of the present invention, its use and operation in and with Fourdrinier suction boxes and its functioning therewith coupled with the advantages thereof will, it is believed, be fully apparent from the above detailed description thereof.

While rubber is the preferred material for forming the casing body of the belt, it should be understood that other elastomers and plastics may be used for the body material, such as for example, synthetic rubber, nylon, Teflon (polytetrafluoroethylene resin), polyethylene resins, polyvinyl resins, and the like. Therefore the term rubber as used herein and in the claims is intended to include such equivalent materials.

While the invention has been specifically described as embodied in a belt for the suction box of a Fourdrinier paper machine, it will of course be understood that the belts of this invention are useful as supports for traveling filter members of deliquefying machines in general and the invention is therefore not limited for use on Fourdrinier paper making machines.

It will be further apparent that many changes may be made in the patterning of the belt and in substitution of the materials therefor without departing from the principles described and from the spirit of the invention defined in the following claims.

We claim:

1. A belt for carrying the wire over the suction box in a Fourdrinier machine the cover of which suction box is formed with groups of longitudinally disposd drainage holes, said belt comprising a flexible rubber casing body provided with groups of longitudinally disposed drainage holes which in the movement of the belt over the suction box are alined with the longitudinally disposed drainage holes in the suction box cover, said belt encasing a strength member comprising a plurality of laminated plies of rubber impregnated fabric sheets, each sheet comprising a fabric woven transversely with straight metal wire filler and longitudinally with an interlaced yarn warp, the metal filler wire functioning to inhibit changes in the width dimensions of the belt so as to maintain alinement between the belt drainage holes and the suction box drainage holes during the wire carrying movement of the belt over the suction box, and the yarn warp functioning to maintain belt flexibility in a belt longitudinal direction.

2. A belt for carrying the wire over the suction box in a Fourdrinier machine the cover of which suction box is formed with groups of longitudinally disposd drainage holes, said belt comprising an endless flexible rubber casing body provided with laterally extending drainage channels provided with drainage holes, said drainage holes being arranged in the belt to form groups of longitudinally disposed holes which in the movement of the belt over the suction box are alined with the longitudinally disposed drainage holes in the suction box cover, said belt encasing a strength member comprising a plurality of laminated plies of rubber impregnated fabric sheets, each sheet comprising a fabric woven transversely solely with straight metal wire filler and longitudinally with an interlaced yarn warp, the metal filler wire functioning to inhibit changes in the width dimensions of the belt despite the drainage channels and holes therein so as to maintain alinement between the belt drainage holes and the suction box drainage holes during the wire carrying movement of the belt over the suction box, and the yarn warp functioning to maintain belt flexibility in a belt longitudinal direction.

3. The belt of claim 1, in which the filler wire is brass and the warp yarn is a flexible fibrous material.

4. The belt of claim 3, in which the fibrous warp material is cotton.

5. The belt of claim 1, in which the warp yarn is substantially larger in gauge than that of the filler wire, and in which the warp yarn is woven tightly under and over the straight filler wire.

6. The belt of claim 5, in which the filler Wire is brass of the order of .00 gauge and the warp yarn is cotton of the order of 12/3 warp.

7. The belt of claim 1, in which the Woven fabric of each ply sheet is encased within and bonded to the rubber which impregnates it and consecutive plies are rubber bonded to each other.

8. A belt for carrying the wire over the suction box in a Fourdrinier machine the cover of which suction box is formed with groups of longitudinally disposed drainage holes, said belt comprising a flexible rubber casing body encasing a strength member, said strength member comprising a plurality of laminated plies of rubber impregnated fabric sheets, each sheet comprising a fabric woven transversely essentially with straight metal wire filler and longitudinally an interlaced yarn warp, the metal filler wire functioning to inhibit changes in the width dimensions of the belt, whereby there is maintained alinement between longitudinally disposed drainage holes of said belt and the said suction box drainage holes during the wire carrying movement of the belt over the suction box, and the yarn warp functioning to maintain belt flexibility in a belt longitudinal direction.

9. A belt comprising an endless flexible rubber casing body provided with laterally extending drainage channels, said drainage channels being arranged in the belt to form groups of longitudinally disposed holes which in the movement of the belt are adapted to stay in alignment, said belt encasing a strength member comprising a plurality of laminated plies of rubber impregnated fabric sheets, each sheet comprising a fabric woven transversely solely with straight metal wire filler and longitudinally with an interlaced yarn warp, the metal filler wire functioning to inhibit changes in the width dimensions of the belt so as to maintain said alignment, and the yarn warp functioning to maintain belt flexibility in a belt longitudinal direction.

References Cited in the file of this patent UNITED STATES PATENTS 1,457,892 Blackwelder June 5, 19 3 2,511,581 Grigsby June 13, 1950 2,784,130 Kalin Mar. 5, 1957 FOREIGN PATENTS 1,179,729 France Dec. 22, 1958 

9. A BELT COMPRISING AN ENDLESS FLEXIBLE RUBBER CASING BODY PROVIDED WITH LATERALLY EXTENDING DRAINAGE CHANNELS, SAID DRAINAGE CHANNELS BEING ARRANGED IN THE BELT TO FORM GROUPS OF LONGITUDINALLY DISPOSED HOLES WHICH IN THE MOVEMENT OF THE BELT ARE ADAPTED TO STAY IN ALIGNMENT, SAID BELT ENCASING A STRENGTH MEMBER COMPRISING A PLURALITY OF LAMINATED PLIES OF RUBBER IMPREGNATED FABRIC SHEETS, EACH SHEET COMPRISING A FABRIC WOVEN TRANSVERSELY SOLELY WITH STRAIGHT METAL WIRE FILLER AND LONGITUDINALLY WITH AN INTERLACED YARN WARP, THE METAL FILLER WIRE FUNCTIONING TO INHIBIT CHANGES IN THE WIDTH DIMENSIONS OF THE BELT SO AS TO MAINTAIN SAID ALIGNMENT, AND THE YARN WARP FUNCTIONING TO MAINTAIN BELT FLEXIBILITY IN A BELT LONGITUDINAL DIRECTION. 